Device to detect skew in fabrics



Aug. 8, 1944. w. c. QBERKIRK DEVICE TO DE'I'EOT SKEW IN FABRIC Filed001;. 2, 1943 R O T N E V m ATTORNE server.

Patented Aug. 8, 1944 DEVICE TO DETECT IN FABRICS William C. Oberkirk,Bronx, N. Y'., assignor to United Merchants & Manufacturers, Inc., Wilmington, DeL, a corporation of Delaware.

Application October 2, 1943, Serial No; 504,697

3 Claims. (01. zc-sn This invention relates to the textile'art and moreespecially to a device for detecting skew of the weft strands of wovenfabrics.

In the art of manufacturing textiles it is common practice to pass thefabric through one or more tenter frames, the purpose of which is wellknown. As the fabric continuously passes through these frames it isgrabbed by the fingers thereof and stretched laterally. This action isapt to throw the weftstrands out of their desired relation perpendicularto the longitudinal axis of the fabric and perpendicular to the warpstrands. Means are available and used in the art for the purpose ofpreventing this distortion or skew. Such means are known and need not bedescribed in detail since they do not form part of the presentinvention. For purposes of identification, refskew or distortion will bereadily apparent. In the absence of distortion the lines of the imagescorresponding to the weft threads at opposite edges of the fabric willbe substantially aligned.

The presence of skew or distortion is indicated by an oifset relation ofthe lines of the pairs of images.

The principles of the invention will be defined in the'claims andillustrated by the followin de scription taken in conjunction with theaccompanying drawing, in which:

Fig. 1 shows diagrammatically a train of fabrictreating.apparatusincluding an embodiment of erence may be had to UnitedStates Patents- 2,209,220, 2,106,611, 2,106,612, and 2,311,406, whichdescribe certain forms of the devices mentioned. While such devices areuseful, they can not be depended upon completely to prevent skew.

It is an object of the present invention to devise I apparatus whichwill enable skew to be readilydetected. I

The apparatus of the p esent inventionmay be employed in conjunctionwith the above menthe present invention;

Fig. 2 is an. enlarged diagrammatic sectional view taken on the line 2-2of Fig, 1; Fig. 3 is a diagrammatic view of apair of images of the weftthreads at opposite edges of the fabric when the weftstrands areproperly arranged and aligned; and

Fig. 4 is a diagrammatic view showing a pair of images of th weftthreads at opposite edges of the fabric when the weft threads are skewedor distorted.

Referring first to Fig. 1, this is essentially a fiow sheet ordiagrammatic view showing a typical or specific treatment of fabricinvolving the use of tenter frames,v in conjunction with which apparatusan embodiment of the invention is diagrammatically indicated at theextreme left, it being understood that this view shows merely one of themany instances in which the invention as disquency, These flashes may beemitted fromagij gaseous dischargelamp by discharging an electriccurrent through the gaseous filling of said lamp at a controlledfrequency. The light from each of the illuminated areas may then be prdjected on any suitable viewing means such as a screen, and said lightdirectedfrom said areas so that the pair of images of the weftstrand atopposite sides of said fabric are grouped in closely juxtaposedpositions visible to the eye of an ob- By suitably correlating thefrequency of the light flashes with the speed of travel of the web orfabric, the images of the weft threads cast upon the screen may appearstationary or moving at such a low rate of speed as to be clearlyvisible, and by juxtaposing the image of the weft threads "rolls 9.being employed to direct the fabric.

closed and claimed herein may be utilized. The fabric I passes from anaccumulation 2 thereof through a mangle 5 provided with treatment rolls6, in which the fabric may be subjected to treatmentwith any desirablefinishing agent, and then to a straightening tenter frame I, suitableguide A skew controlling device indicated generally at I0 may beprovided with the object of automatically preventing. skew and enablingthe tenter frame to straighten out the weft threads or strands.

The fabric then passes over guide roll I2 and drying cans I4 and thenpasses, via guide rolls I5, to a finishing tenter frame I'I providedwith a hot air drier I8, the tenter frame ll being provided with drivemotor I9. The fabric then passes over I guide rolls 20,2 I, 22 and istaken up on accumula tion roll 23. Intermediate the rolls 22 and 23 theinspection and detection device of the present of one edge of the fabricwith those of other, any

invention is employed, that device being further shown in Fig. 2.Opposite each of the edges 26 and 21 of the fabric or web I, there arearranged apair of stroboscope lamps 28. Such lamps per se are known andthe structure need not be described in detail except to state that theycommonly include a transparent envelope containing a rare gas or mixtureof gases and provided with electrodes connected to a source ofdiscontinuous electric current, usually alternating, the fre quency ofwhich is controllable by the timer 38, current being delivered to thelamp through leads 3|, 32, and 33. Between the lamps 28 and the edges26, 21, condensing lens means, indicated generally by 34, are arranged.The lens means 34 concentrates light from the lamp 28 so that a I beamof light is directed transversely of the fabric I through theinterstices between the strands at the areas at the edges 26 and 21thereof. On the other side of the fabric .opposite the lamps 28, meansare provided to pickup the transmitted light and project images of thewarp and weft threads and direct two pairs of images thus produced sothat they are visible to the eye of an observer in closely juxtaposedposition. This means may comprise a telescopic apparatus indicatedgenerally as 35. This comprises a tube 31 with projecting lens meansindicated generally as 38 at each of the two ends thereof. As shown inFig. 2, those ends may be continuations of the tube 31, the axes of saidends being transverse to the axis of the tube 31, the axis of which, asspecifically shown. in Fig. 2, is perpendicular to the longitudinal axisof the fabric I and substantially parallel to the plane of said fabric.Intermediate the ends of the tube 31 the tube 39 projects therefrom atright angles, at one end of which there is provided a viewing screen 40,The tube 39 may have a wall or diaphragm 4| extending longitudinallythereof and dividing it into substantially two passageways. Reflectors43 direct the light emitted by the lamps 28 and transmitted through theinterstices of the fabric I and through the projection lens means 38 onthe screen so that images of the weft and warp strands at the edges 28and 21 are grouped on-said screen in closely juxtaposed position readilyvisible to the eye of the observer. Any suitable magnification of thestrands may be effected by means of the lens system in a manner whichwill be clear. At 45, there is diagrammatically shown a telescopicconstruction to permit focusing adjustment and at 46, a similarconstruction'to provide lateral adjustment of the tube 36 for focusingpurposes and to accommodate different widths of fabric.

In the operation of the device, the operator, knowing the speed oftravel of the fabric as it leaves the tenter frame I! on its way totake-up roll 23, adjusts the frequency of the light flashes emitted bythe lamps 28 so that the images of the warp and weft threads passed uponthe viewing screen 40 either appear stationary or moving at such a lowrate of speed as to be clearly visible as a series of lines, asindicated in Figs. 3 and 4. As above mentioned, distortion of the weftthreads is indicated by the fact that the lines of the image of the weftthreads of the edge 21 are offset in relation to the lines of the imageof the weft threads of the edge 26. When such distortion is detectedthensteps may be immediately taken by known means to adjust the operation ofthe tenter frames to cure this condition.

It is to be understood that the embodiment of the invention-specificallyhereinabove described may be modified by those skilled in the artwithout departing from the principles of the invention as defined in theappended claims. For example, instead of employing light transmittedthrough the interstices of the fabric, the lamps 28 could be arranged onthe same side of the fabric as that in which the telescopic apparatus 36is positioned, in which case reflected light would be employed toproduce images of the strands. It is preferred, however, to employtransmitted light.

I claim:

1. In conjunction with apparatus for finishing woven fabrics including atenter frame and means to continuously pass the fabric in sheet formfrom the tenter frame to a place of disposal at a predetermined linearspeed, a pair of stroboscopic lamps arranged on one side of said cloth,each of said lampsbeing adjacent an edge of said fabric; means to varythe frequency or the light flashes from said lamp in accordance with thespeed of movement of said fabric, said lamps being adapted to direct aseriesof light flashes of controllable frequency transversely of saidfabric and through the interstices of the strandsthereof; a tube havingan axis substantially parallel to the plane of said fabric andpositioned on the other side of said fabric and in adjacent spacedrelation thereto; said tube having projection lensmeans I at each endthereof opposite said lamps, image viewing means intermediate the endsand means to direct the projected pair of images of the warp and weftstrands of the opposite edge portions of said fabric and to groupsaidpair of images so that they are visible to the eye of an observer inclosely juxtaposed position at the viewing means.

2. In conjunction with apparatus for finishing woven fabrics including atenter frame and means to continuously pass the fabric in sheet formfrom the tenter frame to a place of disposal at a predetermined linearspeed, a pair of stroboscopic lamps arranged on one side of said clothand to project their beams through limited areas of the fabric spacedapart widthwise thereof; means to vary the frequency of the lightfiashesfrom said lamp in accordance with the speed of movement of said fabric;a housing positioned on the other side of the fabric from said lamps andin adjacentspaced relation thereto; said housing having projection lensmeans at each end thereof opposite said lamps, image viewing meansintermediate the ends and means to direct the projected pair of imagesof the warp and weft strands of said spaced apart areas and to groupsaid pair of images so that theyare visible to the eye of an observer inclosely juxtaposed position at the viewing means.

3. In conjunction with apparatus for finishing woven fabrics including atenter frame and means to continuously pass the fabric in sheet formfrom the tenter frame to a place of disposal at a predetermined linearspeed, a pair of stroboscopic lamps arranged on one side of said clothand to project their beams through limited areas of the fabric spacedapart widthwise thereof means to vary the frequency of the light flashesfrom said lamp in accordance with the speed of movement of said fabric;means located on the other side of the fabric from said lamps to directthe light from the illuminated areas and to create images of the warpandweft threads of said areas; and means to group said images so as tobe visible in closely juxtaposed position.

WILLIAM C. OBERKIRK.

